66228261 has 24 divisors (see below), whose sum is σ = 99705312. Its totient is φ = 39045600.

The previous prime is 66228259. The next prime is 66228287. The reversal of 66228261 is 16282266.

66228261 = 679² + 680² + ... + 799².

It is not a de Polignac number, because 66228261 - 2¹ = 66228259 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66228221) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10966 + ... + 15896.

It is an arithmetic number, because the mean of its divisors is an integer number (4154388).

Almost surely, 2^66228261 is an apocalyptic number.

It is an amenable number.

66228261 is a deficient number, since it is larger than the sum of its proper divisors (33477051).

66228261 is a wasteful number, since it uses less digits than its factorization.

66228261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4993 (or 4982 counting only the distinct ones).

The product of its digits is 13824, while the sum is 33.

The square root of 66228261 is about 8138.0747723279. The cubic root of 66228261 is about 404.5893536214.

The spelling of 66228261 in words is "sixty-six million, two hundred twenty-eight thousand, two hundred sixty-one".